1. Field of the Invention
This invention relates to a vehicle-based headway collision avoidance trainer. The invention is particularly useful for instructing student drivers to maintain safe following distances behind other motor vehicles while the student is behind the wheel of an ordinary driver education vehicle. The combined effects of driver, vehicle, and roadway factors determine safe following distances according to physical laws, which are not intuitive and not easily separable in everyday driving. For example, slow student reaction-time, hard-braking by a leading-vehicle, and wet roadways, require that the student maintain a longer headway distance. In using the trainer, actual or simulated driver, vehicle, and roadway conditions are independently selectable by the driving instructor, the combination of which is used to compute a danger of headway collision distance. According to the present invention, unique instructional auditory and visual displays are attended by the student driver, and controls and displays are used by the instructor, which are specifically intended for teaching headway safety in the environment of a moving vehicle.
According to the National Highway Traffic Safety Administration, rear-end collisions are a leading cause of injury, death, and loss of property. Rear-end crashes involving passenger-vehicles was the second leading crash type in 1993, representing 26% of all crashes. For single-unit and combination-unit trucks, the rear-end collision was the most prevalent of all specific crash categories, representing 26% and 19% of all crashes, respectively. However, younger drivers are the highest risk group. Motor vehicle crashes are the leading case of death for drivers 15 to 20 years of age. Drivers 15 to 19 years of age were nearly three times more likely to strike another vehicle, and nearly twice as likely to be struck. The challenge for drivers is that traffic density has increased and there are greater numbers of commercial trucks and sport utility vehicles on roadways. Large vehicles can block the view of traffic ahead of the large vehicle, ordinarily used to maintain a safe distance. In this regard, the present invention can help reduce rear-end crashes by providing an in-vehicle environment for students to acquire the knowledge and learn behaviors that result in safe following distances.
2. Prior Art
Collision avoidance training technology has been limited to desktop video-based driving simulators, expensive research simulators, and instructional media. In previous research reported in Commercial Motor Vehicle Simulation Technology To Improve Driver Training, Testing and Licensing Methods FHWA-MC-96-003 Final Report, April (1966), driver training experts were asked to rate the importance of various simulator training objectives. Following-distance was rated nearly equal to that of driving forward, and was rated the 7th most important objective of 23 in simulator training. However, whereas, all evaluated simulators were judged as adequate in teaching forward driving skills, following-distance was judged as adequate in only 6 of the 12 simulators reviewed. Furthermore, only one of these 6 was manufactured in the U.S., a high fidelity full mission simulator valued at $900,000. Other U.S. built systems were rated as xe2x80x9cnot-adequatexe2x80x9d or xe2x80x9cnot-providedxe2x80x9d with regard to teaching following-distance. These systems were low-fidelity or mid-level fidelity part-task simulators and cost as much as $250,000. The failure of even the most expensive simulators to teach safe following distance is the shortfall of reproducing the visual cues required for judging distance.
The object of the present invention is to provide accurate instructional feedback to student drivers on maintaining safe following distances, under actual or simulated driver, roadway, and traffic conditions, with the student behind the wheel of an ordinary driving education vehicle.
It is a further object of the invention to provide unique auditory and visual displays for the student driver, and controls and displays for the driving instructor specifically intended for teaching headway safety in the environment of a moving vehicle.
According to the present invention, there is provided a vehicle-based headway collision avoidance trainer for the purpose of training student drivers to maintain safe following distances behind other motor vehicles. Unlike other known means of headway distance training, the present invention is intended for use by driving educators in the environment of an ordinary training vehicle while the student driver operates the motor vehicle in response to actual or simulated driver, roadway and traffic conditions. There is provided an integrated collection of special auditory and visual displays attended to by the student, and controls and displays used by the instructor that are unique for teaching headway safety in the context of a moving vehicle. The invention pertains to educating student drivers of passenger vehicles, trucks, busses, and other vehicles, but also pertains to drivers that require driving rehabilitation, training elderly drivers to adjust to losses in perceptual judgement, teaching advanced driving skills, and special driving skills used in law enforcement.
Further, according to the present invention, there is a vehicle-based headway collision avoidance trainer comprising: means for measuring the distance between the training vehicle and a second vehicle traveling in the forward path of the training vehicle; means for measuring the speed and direction of the training vehicle; means for sensing student braking; means for sensing turn-signal activation; means for measuring the reaction-time of the student driver; means for sensing roadway topography and temperature; a computer for receiving a number of parameters, from said sensing means, and for computing from these and other parameters the speed and direction of the leading vehicle, the stopping time of the training vehicle and leading vehicle, and the danger-of-headway-collision; auditory and visual training displays and warnings actuated by the computer when the danger-of-headway-collision distance is computed; and controls for setting other parameters, which are used by the instructor for teaching headway safety in the context of a moving vehicle.
According to further features of the preferred embodiments, below, the trainer includes a main control panel for selecting one of three instructional displays and one of three instructional methods. One display and one method are continuously visible. Thus, a total of nine pairs of display and method combinations are selectable, and each combination provides for the unique visualization of the training environment and control of the training experience. It is an advantage of the present invention that 1) the combinations of displays and methods are easily selectable by the instructor in a moving vehicle, and 2) the instructor is not distracted by a complex user interface. In other embodiments, additional or other displays and methods may be selectable from the main panel. It is also an advantage of the main control panel that although separate instructional displays may be selected, there is a permanent visual display of the danger of headway collision, an indicator for showing the data processing state of the trainer, and controls for setting conditions for limiting sensor data processing.
According to another feature of the preferred embodiments, below, the trainer includes a danger of headway collision display on the main control panel, which is continuously visible and particularly useful for teaching headway safety in the environment of a moving vehicle. According to one embodiment, the display is a horizontal bar graph, which increases in value from left to right. There are two independent scales. Each scale uses the entire area of the bar graph. The first scale could be colored light red and shows the level of increasing danger up to the following distance where a headway collision would be imminent. After the color of the first scale fills the bar graph, and the distance between vehicles closes further, the display is cleared and the second scale begins again from the left. The second scale could be colored dark red and shows the level of increasing danger that exceeds the minimum recommended following distance. The display is particularly useful for teaching headway safety in the environment of a moving vehicle because it provides 1) permanent means of visual feedback to the student that is intuitive and non-distracting, 2) two separate levels of managing headway distance, prior to imminent danger and within the danger xe2x80x9czonexe2x80x9d, and 3) redundant visual indication of computer generated auditory and instructional speech feedback.
According to still further features of the preferred embodiments, below, the trainer includes a settings control on the main control panel, which is useful for limiting sensor data processed by the computer. Limiting the sensor data processed by the computer is particularly useful for teaching headway safety in the environment of a moving vehicle because 1) non-accurate or inappropriate training feedback can distract and confuse the student, and 2) some sensors require calibration for providing accurate measurements. Regarding the distance measuring sensor, the instructor can select target vehicles within a specified range, calibrate sensor input to reference all distance measures from the front bumper of the training vehicle (if the sensor is located elsewhere on the vehicle), and disable instructional audio and visual feedback until a selected time expires following a full stop and/or after the training vehicle attains a specified speed. It is an advantage of the present invention that the latter selected delays in processing eliminate annoying alarms that may occur during irregular distances and speeds during traffic startup, and/or while driving at lower speeds. With regard to ensuring the accuracy of the speed measurement, there is also a control for calibrating the computed speed measurement with the actual speed of the training vehicle.
According to still another feature of the settings control on the main control panel, there are controls for setting computer generated speech feedback and auditory alarms. Auditory feedback is particularly useful for teaching headway safety in the environment of a moving vehicle because it 1) enables the driver to maintain eyes on the road, and 2) facilitates learning by the student comparing observations of the headway environment with the instructional feedback from the trainer regarding that environment. Feedback includes verbal instruction based on measured trends in student driving performance, and provides remarks to the student regarding their performance. There may be a variety of style and content in verbal feedback, including the use of humor, sarcasm, and different voices. Verbal feedback may be provided through the computer in the form of digitally recorded comments or synthetic speech. Additional auditory features of the present invention include tonal alarms that indicate the moment to moment danger of a headway collision, the operational state of the trainer, violations of selected speed and distance limits, and naming of a function when that function is selected.
According to another feature of the preferred embodiments, below, the trainer includes a simulation method selected on the main control panel which is useful for reproducing the conditions of driver reaction time, braking behavior, and roadway conditions. The simulate method is particularly useful for teaching headway safety in the environment of a moving vehicle because 1) the instructor can change settings to mirror actual driving conditions or to illustrate the separate or combined effects of extreme conditions; for example, slow student reaction time and expected hard braking by the leading vehicle driver would result in a headway warning issued at a farther following distance, than if the student reaction time were faster and the expected leading vehicle braking force were softer, and 2) the student is able to form better judgements about maintaining safe following distances by understanding the effect of conditions on the physical capability of the vehicle to stop. From the selections and measures using the simulation method, when applied to the current distance and vehicle speeds, the resulting danger of headway collision is displayed by the danger-of-headway-collision bar graph on the main control panel, as well as on the time-to-collision graph on the history display.
According to a further feature of the simulation method, the instructor can demonstrate the effects of student reaction time by either selecting one of several reaction times from a list or by implementing real-time student reaction time tests. The selection or measurement of student reaction time is particularly useful for teaching headway safety in the environment of a moving vehicle because longer delays in driver braking responses can greatly lengthen the safe following distance. It is an advantage of the present invention that there are three methods for measuring student reaction time. The first is implemented using the instructors computer, whereby the student uses the trainer interface to respond to randomly presented signals. The second method requires the student to initiate a brake pedal response to signals randomly presented by the trainer. The third method measures real time student braking delays in response to the danger of headway collision warning.
According to a further feature of the simulation method, the instructor can demonstrate the effects of driver braking force by separately selecting deceleration rates for the leading vehicle and training vehicle. The simulation of expected braking force by drivers is particularly useful for teaching headway safety in the environment of a moving vehicle because expected braking force can greatly lengthen the danger of headway collision distance. However, the effects of braking force by each driver has an opposite effect on the requirement to increase or decrease following distance. It is an advantage of the present invention that a unique display is provided to illustrate the counterintuitive relationship. For example, whereas, expected hard braking by the leading driver would result in a warning to increase headway distance because a shorter stopping distance is expected, softer braking by the student driver would also result in a longer headway because a longer stopping distance is expected.
According to still another feature of the simulation method, the instructor can demonstrate the effects of roadway conditions by separately selecting roadway, traffic, and vehicle conditions. The simulation of roadway, traffic, and vehicle conditions is particularly useful for teaching headway safety in the environment of a moving vehicle because risky roadway conditions can greatly lengthen the danger of headway collision distance. The instructor can select the road condition as wet or dry, and road visibility as ok or poor; traffic density as low or high, and braking speed as slow or fast; and the leading vehicle as a car or truck, and the training vehicle weight as normal or heavy. The risk condition selection is highlighted, and each risk causes a cumulative time penalty in computing the danger of headway collision. The time penalty results in a headway warning that occurs at a greater following distance. It will be appreciated that other or additional roadway conditions may be selectable in other embodiments, and other means of increasing headway from risk factors may be implemented.
According to still further features of the preferred embodiments, below, the trainer includes a limit-alarms method control on the main control panel, which is useful for the instructor to select safe driving limits for the student driver. Driving limits include the minimum following distance between the training vehicle and a leading vehicle, the minimum following time xe2x80x9crulexe2x80x9d, e.g. two-second rule (below), and the maximum speed the student may travel. It will be appreciated that other embodiments of the present invention may include other or additional limits. The limit alarms control is particularly useful for teaching headway safety in the environment of a moving vehicle because it provides a means for the student to learn to maintain safe following distances within fixed limits. Whereas, the simulation method teaches the student to anticipate and judge the driver, braking, and roadway factors that require different following distances, the limit alarms method is more intuitive. However, the limit alarms method of headway training can provide an introductory experience using the trainer, prior to learning more complex collision avoidance concepts using the simulation method.
According to a further feature of the preferred embodiments, below, the trainer includes a following-time rule or xe2x80x9crange ratexe2x80x9d method selected on the main control panel, which is useful for instructing the student according to traditional training concepts. For example, a two-second following xe2x80x9crulexe2x80x9d involves a two-second count from the time the leading vehicle passes a roadside landmark until the landmark reaches the following vehicle. The following-time method provides a general rule of thumb for maintaining distance. Following time or range rate is simply the amount of time it takes for the training vehicle to traverse the distance to the leading vehicle. Unlike the simulation method, the following time method does not provide first hand experience about the separate and combined effects of driver, roadway, and traffic conditions. According to the features of the following-time method, the preferred embodiments include the automatic measurement of the headway distance, a means for the instructor to select one of several following times, and a means to graphically monitor student history in maintaining a selected following time. It is an advantage of the present invention that the student receives verbal feedback from the computer, based on performance history, when the measured following time is less than the desired following time.
According to still further features of the preferred embodiments, below, the trainer includes a geometry display selected from the main control panel, which is useful for indicating the relative motion of the leading vehicle with respect to the training vehicle. The geometry display is particularly useful for teaching headway safety in the environment of a moving vehicle because the student can be alerted to conditions where the motion of the leading vehicle will 1) result in a head-on collision, 2) is stationary in front of the training vehicle, 3) just cut in front of the training vehicle, or 4) is traveling normally in the forward path of the training vehicle. It will be appreciated that additional or other motion geometries may be sensed in other embodiments. It is also an advantage of the invention that when the geometry is detected, the sensed motion of the leading vehicle is verbally announced by the trainer. Therefore, the student can verify and learn through observation of the forward scene, when certain geometries present a danger of headway collision. Lastly, in some embodiments the student braking responses to motion geometries is used to automatically compute the student""s reaction time.
According to still another feature of the preferred embodiments, below, the trainer includes a time-to-collision xe2x80x9chistoryxe2x80x9d display selected from the main control panel. The time-to-collision display is useful for teaching headway safety in the environment of a moving vehicle because the time-to-collision measure is the danger-of-headway-collision computed directly from the driver, roadway, and vehicle conditions selected and measured using the simulation method. The history display is particularly useful for graphically showing the measurement and history of the student maintaining a safe headway distance. In addition, the time-to-collision measurement is the value continuously displayed by the danger-of-headway-collision bar graph on the main control panel. It is an advantage of the present invention that the content of verbal feedback by the computer to the student is based on the trends the computer detects in the history of the time-to-collision measurement. Whereas, verbal feedback and alarms from other displays and methods that comprise the trainer are active only when that display or method is selected, the verbal feedback regarding the time-to-collision history and danger of headway collision is constantly enabled.
According to a further feature of the preferred embodiments, below, the trainer includes a measurements display selected from the main control panel, which is useful for providing a moment to moment numerical display of training vehicle and leading vehicle speeds, the distance between the vehicles, and summary measures of student performance. The measurements display is particularly useful for teaching headway safety in the environment of a moving vehicle because the measures provide the instructor with information about student progress. Specifically, the cumulative number of violations or exceeded limits are displayed, e.g. following-time rule, speed, distance, and time-to-collision. It will be appreciated that other performance measures may be used or included in other embodiments of the invention.
According to still another feature of the preferred embodiments, below, included is the means for improving the safe use of the headway trainer. First, the student should not be distracted by auditory feedback while the student is engaged in certain traffic maneuvers, e.g. lane change, merging, braking, turning. It is an advantage of safe operation that the trainer tests for braking and the activation of a turn signal, which indicates that the student is maneuvering the vehicle. Second, it is an advantage of safe operation that the trainer tests for a line-of sight condition. Some line-of-sight sensors, e.g. laser radar, can return false measurements from roadside objects that are detected while the student negotiates a curve. Therefore, the trainer senses a change in heading, which may result in a false alarm. Third, it is an advantage of safe operation that the trainer automatically senses roadway topography and temperature for the purpose of presetting deceleration rates and/or time penalties. For example, roadway pitch angle may be used to automatically increase the following distance when traveling downhill.
Further features and advantages will be apparent from the description below.